1) Can Diablo be killed by Blood Raven's lightning after she dies? How about Shenk's storm after he dies?

2) If Diablo was spawned in place of Hephasto and lured to Chaos Sanctuary, could he be killed by triggering regular Diablo?

3) If Diablo was lured in while regular Diablo has already spawned (ie, having them both around simultaneously), could any oddities be triggered? For example, could killing Uber Diablo cause the quest to be completed?